Abstract

Epoxy-polyhedral oligomeric silsesquioxane (POSS) nanocomposites were prepared by incorporating POSS nanofiller into the epoxy-amine network. The monofunctional epoxy-POSS monomer or nonfunctional octaphenyl POSS unit were applied to reinforce the epoxy network by producing the nanocomposite with chemically bound pendant POSS or physically admixed POSS. The combination of reactive and unreactive POSS, leads to a synergistic effect and to the most efficient reinforcement of the epoxy network. Both polymer-POSS and POSS–POSS interactions are present in the system and lead to a strong physical crosslinking through the path polymer-bound POSS-unbound POSS domain. The nanocomposite was modified by incorporation of the thermoreversible Diels–Alder (DA) type network. The produced interpenetrating network composed of the irreversible reinforced epoxy and the reversible DA networks exhibits an efficient self-healing capability. This strong nanocomposite, showing a modulus of 800 MPa at room temperature, was healed with an efficiency of 61%. The developed stiff nanocomposite is shown to be a promising material because self-healing of strong thermosets is still a big challenge. With the increasing content of POSS nanofiller and heterogeneity of the nanocomposite, however, the healing efficiency diminishes. The insufficient contact of crack surfaces due to involved inhomogeneities results in a worse sealing of the material crack.

摘要

环氧多面体低聚倍半硅氧烷 (POSS) 纳米复合材料是通过将 POSS 纳米填料掺入环氧-胺网络中来制备的。单官能环氧-POSS 单体或非官能性八苯基 POSS 单元用于通过生产具有化学结合侧链 POSS 或物理混合 POSS 的纳米复合材料来增强环氧网络。反应性和非反应性 POSS 的组合导致协同效应和环氧树脂网络的最有效增强。聚合物-POSS 和 POSS-POSS 相互作用都存在于系统中，并通过聚合物结合的 POSS-未结合的 POSS 域的路径导致强烈的物理交联。通过加入热可逆狄尔斯-阿尔德 (DA) 型网络对纳米复合材料进行了改性。由不可逆增强环氧树脂和可逆 D​​A 网络组成的互穿网络表现出有效的自愈能力。这种坚固的纳米复合材料在室温下显示出 800 MPa 的模量，愈合效率为 61%。开发的硬纳米复合材料被证明是一种很有前途的材料，因为强热固性材料的自愈仍然是一个巨大的挑战。然而，随着 POSS 纳米填料含量的增加和纳米复合材料的异质性，愈合效率降低。由于所涉及的不均匀性，裂纹表面的接触不足导致材料裂纹的密封性较差。开发的硬纳米复合材料被证明是一种很有前途的材料，因为强热固性材料的自愈仍然是一个巨大的挑战。然而，随着 POSS 纳米填料含量的增加和纳米复合材料的异质性，愈合效率降低。由于所涉及的不均匀性，裂纹表面的接触不足导致材料裂纹的密封性较差。开发的硬纳米复合材料被证明是一种很有前途的材料，因为强热固性材料的自愈仍然是一个巨大的挑战。然而，随着 POSS 纳米填料含量的增加和纳米复合材料的异质性，愈合效率降低。由于所涉及的不均匀性，裂纹表面的接触不足导致材料裂纹的密封性较差。